Design of frequency synthesizer for wireless communication

Modems play a vital role in the field of communication, Suitable and stable carrier frequency is required for any efficient modulation process. This paper proposes a method of generating carrier frequencies by using the concept of phase locked loop (PLL). The proposed method is implemented using the synthesizer chip ADF4351 and PIC32 microcontroller. ADF4351 can generate frequencies of range 35MHz to 4.4 GHz with external loop filter and reference frequency along with additional features like generating stable frequency in fractional-N mode and integer-N mode, fast lock mode, mute mode. The proposed methodology has successfully been experimented and verified for the following frequencies with precision up to two decimal points: 1GHz, 1235.54MHz, 1500.25MH, 1700MHz, 1800.665MHz, and 1995.00MHz. The obtained frequency components of the signals are very useful in the field of military and commercial application.